Polishing.



UNITED STATES PATENT OFFICE.

PETER rmnmN, or WASHINGTON, DISTRICT or COLUMBIA, ASSIGNOB To MAGNETIG PIGMENT COMPANY, or NEW YORK, N. Y., A CORPORATION on NEW YORK.

POLISHING.

1,025,945, Specification of Letters Patent.

No Drawing.

To all whom it may concern:

Be it known that I, PE ER FIREMA a citizen of the United States, residing at Washington, District of Columbia, have invented certain new and useful Improvements in Polishing; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as-will enable others skilled in the art to which it appertains to make and use the same.

My invention relates tothe production of a high polish upon appropriatesurfaces, and particularly upon surfaces of glass (as, for instance, optical lenses, mirrors and the like), and upon certain metals to which a characteristic luster is simultaneously imparted, as, for instance, gold, platinum, sil-' ver, copper, and their alloys.

In carrying out my invention, I avail myself of the discovery made by me that the most finely divided chemically precipitated black magnetic ferro-ferric oxid, although of so fine a texture as to readily yield an impalpable powder, is, under certain conditions, capable of effectively polishing surfaces of the hardness of glass, and with a celerity and efficiency superior to that of certain oxids of iron found in nature, which, on pulverization, yield a powder decidedly rough to the touch and which are widely used in lens polishing on a large scale and for similar a plications.

In other words, I have foun that precipitated ferro-ferric oXid, notwithstanding its impalpable fineness, develops an unexpected cutting power of such a uniform and regulable character that it maybe relied upon with certainty for the production of the best standard effects, when applied under conditions of use which I have ascertained by extensive experimentation.

The importance of this discovery will be the more apparent when it is remembered that in polishing with the more or less rough powders scratches are not infrequently produced which prolong the polishing operation even in the hands of the most skilful operators, and which sometimes are apparent in the finished article despite the effort made to entirely remove them. This difliculty is entirely obviated by the employment of the precipitated black, magnetic ferro-ferric oxid in accordance with my invention.

In carrying out my invention for the pol- Application filed October 31, 1907. Serial No. 400,004.

ishing of glass, I employ a liquid vehicle, preferably water, as a medium for bringmg the precipitated ferro-ferric oxid into a condition appropriate for use. Mixed with water in the form of a paste, the precipitated ferro-ferric oxid will cake on losing water, and, if in this condition, it is rubbed against glass, it will produce deep scratches. For a time, this seemed to be a circumstance fatal to the successful employment of the precipitated ferro-ferric oxid as a glass polisher. Further experimentation, however, developed the fact that if the thin paste is inserted between the polisher, which is lined with thick felt, and the lens embedded in the pitch which covers the block, the friction incident to the rubbingof the polisher against the lens, raises the temperature sufficiently to gradually evaporate a portion of the water of the layer of paste, causing the paste to gradually approach the cakey condition. Thereupon, it develops its cutting power, without scratching, which would take placev if it were permitted to become too dry. On the other hand, a certain thickness or body of the paste must be maintained, if polishing at all is to take place, and I have ascertained that there is a practical range of effective polishing action between the point at which the paste becomes sufliciently dry to develop the quick cutting action, and that at which it is so dry as to threaten damage by scratching and that this range is sufficiently wide to insure the uniform production of finished articles in a highly polished condition devoid of scratches. The operator quickly ascertains the proper consistency of the partially caked paste to produce the best results and maintains this consistency by adding thin paste from time to time. Before the cutting power of the precipitated ferro-ferric oxid was understood, it seemed incomprehensible that this impalpable owder should not only do as effective polishing as the much rougher materials now in use, but should actua ly accomplish it in a considerably shorter time. It is a quick polisher.

In. making the preliminary paste, I may conveniently employ as the ingredients of the mixture say ten pounds of the recipitated ferro-ferric magnetic oxid tove gallons of water, although I do not restrict myself to these proportions. The paste mixacceptable to the eye,

iar to. itself alone, To gold it imparts an admirable rich dark.

ture is to be stirred thoroughly at the time of application to the lens, and is preferably applied by means of a brush. The felt finallybecomes saturated with the paste and is then in its most eificient condition. The polisher is usually arranged for continuous rotation, and the lens supporting block may either be stationary or may revolve in the same or in an opposite direction to that of the polisher, or may reciprocate, z. (1., revolve, alternately, first in one direction, and then in the other.

--I-have just shown how well the recipitated magnetic ferro-ferric oxid len s itself to the polishing of glass. It has also very striking and characteristic properties, peculin the polishing of metals.

luster, in contradistinction to the lighter color imparted by jewelers rouge. So also, to platinum, it gives a luster particularly and which, so far as am aware, is not produced by the use of other polishing agents. It produces a like effect upon brass.

In the polishing of metals, the precipitated magnetic ferro-ferric oxid is best used in the form of sticks, in which certain waxes or stearic acid, with fats are used as bindin material, and, in this form, it is also wefi adapted for polishing hard rubber, mother of pearl, and the like. In compounding such pohshing sticks, I may conveniently use as theingredients thereof, say 100 pounds of the precipitated magnetic ferro-ferric oxid to 17 pounds of stearic acid and 3 pounds of beef tallow, the stearic acid and tallow being first melted and the precipitated ma m neticferro-ferric oxid being then thorough y arid uniformly incorporated in it by vi orous stirring. The addition of tallow tends to soften the st1ck and increase the cutting quantities of other ingredients is power of the-compound. These proportions are most suitable for polishing gold; for platinum, a trifle more tallow to the same desirable; while for brass and German silver, a still larger proportion of tallow improves the cutting power'and so the celerity of polishing. If desired, I may add a small quantity of rouge to the composition, to vary the luster of the finished article. I

I do not claim herein the method of polishing described, which consists in mixing precipitated-magneticferro-ferric oxid with a liquid to form a paste, applying the paste between the polisher and the article to be polished, causing a portion of the liquid to gradually evaporate, by friction, and maintaining the preci itated magnetic ferro-ferric oxid, during t e olishing operation, in a condition intermediate between its initial pastin'ess and'such dryness as would scratch the article operated upon; for the reason that the same is claimed in another a plication filed by me as a division hereof, gerial No. 421,376.

What I claim is 1. A polishin agent,.consisting of a suitable vehicle, an an abrading material whose princi al constituent is'precipitated magnetic erro-ferric oxid; substantially as described.

2. A polishing agent, consisting of a suitable vehicle, and an abrading material made up of a mixture .of precipitated ma netic ferro-ferric oxid and rouge; substantia ly as described.

In testimony whereof I afiix my in presence of two witnesses.

PETER FIREMAN.

signature,

Witnesses THoMAs' DURANT, Cms. J. ONnnm. 

